There are three different scanners on the market, one is the paper-feed type, one is the platform type and the third one is the hand-held type. The paper-feed type scanner uses a paper-feed mechanism to suck in the paper placed inside the scanner, which has better performance and resolution when compared with the platform and the hand-held types. However, the paper-feed type scanner still suffers from shortcomings.
When the paper is being sucked in the scanner by the paper-feed mechanism and guided by the paper-guiding bar, the thickness and the flatness of the paper being scanned affect the overall performance of the scanned result. Sometimes, the scanned result is not as good as expected when the paper is wrinkled and is not able to completely engage with the paper-guiding bar. Therefore, blur and stain may appear on the scanned paper. Furthermore, due to the flatness of the paper, the paper scanned may be shifted during engagement with the paper-guiding bar. In order to overcome the shortcoming, a scanner with a spring to straighten the paper is introduced to the market. This kind of scanner though solves the paper flatness problem, the paper-guiding bar movement is still limited. That is, I the thickness of the paper scanned is too thick, the paper-guiding bar is not able to adjust its movement to cope with the thickness change of the paper.
To overcome the shortcomings, the present invention intends to provide an improved paper pressing device for a scanner to mitigate or obviate the aforementioned problems.